In recent years, lithium ion rechargeable batteries have attracted attention for the application to hybrid vehicles, electric vehicles and the like. In addition, rechargeable batteries are charged with electrical energy that has been generated and supply the charged electrical energy, and thus, there is a large potential for various applications which also has attracted attention.
A typical example of an all-solid rechargeable battery, particularly an all-solid lithium rechargeable battery, where no liquid is used for the electrolyte is a thin film rechargeable battery. Such a thin film rechargeable battery is fabricated by forming films on a substrate such as of silicon in accordance with a vapor deposition method, a PLD (pulse laser ablation) method, a sputtering method, a CVD method and the like, and is characterized in that the film thickness is as thin as several μm.
Such a thin film rechargeable battery is characterized in that the level of safety is high due to the use of a solid electrolyte, and it is possible to integrate it into devices of various sizes. A metal oxide or a metal oxoate(oxyacid salts) is used as the positive electrode of a thin film rechargeable battery. In addition, a metal oxide, a metal oxoate or any of these of which the oxygen that forms these is partially replaced with nitrogen is used as the solid electrolyte. An alkali metal such as lithium or sodium is used as the negative electrode (see Patent Literature 1 or Patent Literature 2).
FIG. 12 is a diagram illustrating the structure of a conventional all-solid Li ion battery where films of a current collector 52, a positive electrode 53 and a solid electrolyte 54 are formed on a substrate 51. Next, an annealing treatment is carried out in order to crystalize the positive electrode 53. Then, films of a negative electrode 55 and a current collector 56 are formed. In this case generally, Pt or SUS is used as the current collectors 52 and 56, LiCoO2 is used as the positive electrode 53, LiPON is used as the solid electrolyte 54, and metal Li is used as the negative electrode 55.